1. Field of the Invention
The present invention deals with coke ovens and, in particular, with coke oven charging hole covers.
2. Description of the Prior Art
Coke ovens are conventionally filled with coal in preparation for the coking process through a plurality of charging holes located on the battery top. The removable covers for these charging holes have generally consisted of a single cast iron plate which rests on a frame surrounding the charging hole so as to form a peripheral gravity seal around the charging hole where the cover contacts the frame. These plates, however, are known to reach such high temperatures during the coking process that they may tend to warp, and if such warping does occur they may no longer form a gas tight seal with the charging hole frame. The escape of pollutants from inside the oven may, therefore, result. Furthermore, because heat is conducted more efficiently through these cast iron charging hole covers than through other sections of the oven roof, it is believed that this cast iron construction is responsible for the occurrence of an undesirable concentration of heat directly above the covers. Various suggestions have been made for alleviating the above mentioned problems. U.S. Pat. No. 3,900,369, for example, proposes that a cover be constructed by bolting or otherwise fixing a preformed refractory plate section below an iron cover top section. While this cover would appear to reduce heat flow from inside the coke oven, it may under certain circumstances, be preferable, for cost and durability reasons, to employ a cover which is constructed mostly of metal but which still does not tend to become excessively hot or concentrate heat in the space directly above it. It is, therefore, the object of the present invention to provide a heat dissipating charging hole cover which has the above mentioned characteristics.